Some of the outdoor units of air conditioning systems, which are one type of refrigerator, are of the type that draw in air from a side face, exchange heat with the air, and blow the air out through a top face. This kind of outdoor unit is used to condition the air of office buildings and the like; it is installed on the roof of a building and connected to a plurality of indoor units through communication pipings. This kind of outdoor unit is provided with a generally rectangular-parallelepiped-shaped casing inside of which are provided such devices as a compressor, a heat exchanger, and a blower fan. An air inlet is provided on a side face of the casing and an upwardly directed air outlet is provided on a top face of the casing. More specifically, air inlets are provided in the two side faces and the rear face of the casing but not the front face. The heat exchanger serves to exchange heat with the air drawn in from the air inlets and is arranged inside the casing so as to face each of the air inlets. The blower fan is a propeller fan for discharging air through the air outlet after the air has exchanged heat at the heat exchanger and is provided in an upper portion of the casing in such a manner as to be aligned with the air outlet. Additionally, an electrical equipment box that houses an inverter, a control circuit board, and other electrical components is provided inside the casing in such a manner as to face the front face so that it can be accessed from the front face side. More specifically, the electrical equipment box is a generally rectangular-parallelepiped-shaped box provided below the blower fan when viewed from the front face side of the casing. When viewed from the top face side of the casing, the electrical equipment box has an elongated shape that runs toward both side faces and the amount by which it protrudes toward the rear face is small. When viewed from the front face side of the casing, the casing is divided into two spaces, i.e. a left space and right space (see, for example, Japanese Laid-Open Patent Publication No. 6-281204).
With an outdoor unit provided with such an electrical equipment box, the blower fan is driven and air is drawn in through the air inlets. Then, after the air exchanges heat with a refrigerant in the heat exchanger, the air is discharged from the air outlet. The air that is drawn in through the air inlets and discharged from the air outlet due to the blower fan being driven flows from bottom to top inside the casing (see, for example, Japanese Laid-Open Patent Publication No. 8-128678).
The outdoor unit just described requires a large capacity in order to accommodate as many indoor units as possible. However, simply speaking, in order to increase the capacity of the outdoor unit, it is necessary to enlarge the heat exchanger and the blower fan and, as a result, the size of the outdoor unit becomes large. This increase in size causes such problems as a decrease in the loading efficiency of the unit during transport and difficulty in carrying the unit to such places as the roof of a building. Consequently, it is necessary to make the outdoor unit more compact in addition to increasing the capacity of the outdoor unit. It is particularly necessary to reduce the size of the outdoor unit when viewed from the top face because the size of the outdoor unit when viewed from the top face has a large effect on the loading of the unit during transport and the carrying of the unit to such places as the roof of a building.
However, if the size of the outdoor unit when viewed from the top face is constrained, the amount by which the electrical equipment box protrudes into the portion where the blower fan is conducting its blowing work will be larger because the blower fan will be larger due to the increase in capacity of the outdoor unit. As a result, the flow of air from bottom to top inside the casing will be impeded and the air flow resistance will increase. Consequently, there is the possibility that the blowing performance of the blower fan will decline and that noise will increase.
Meanwhile, the electrical equipment box must have a prescribed volume in order to house all of the various electrical equipment components. It is also necessary to cool the electrical equipment box on a continuous basis when the outdoor unit is in operation because several electrical components that emit large amounts of heat are housed inside the electrical equipment box. Consequently, the electrical equipment box must be arranged so as to protrude into the portion where the blower fan is conducting its blowing work by the amount necessary to accomplish the cooling.
Also, the electrical components housed in the electrical equipment box of the outdoor unit described above are arranged in such a manner as to be separated according to function and characteristics. For example, electrical components that emit large amounts of heat (high heat emission components)—including strong current components such as inverters and reactors—are arranged in one of the two aforementioned left and right spaces and electrical components that emit small amounts of heat (low heat emission components)—including weak current components such as control circuit boards—are arranged in the other of the two planarly divided spaces. Moreover, it is necessary to make the outdoor unit described above more compact; particularly from the perspective of transport, it is necessary to reduce the size of the outdoor unit when viewed from the top face. However, if the size of the outdoor unit when viewed from the top face is constrained, it becomes spatially difficult to arrange the electrical equipment box (which has two spaces, one on the left and one on the right). Consequently, it is necessary to make the electrical equipment box more compact.
Since the sizes of the electrical components arranged inside the electrical equipment box are various, the amount by which the electrical equipment box protrudes from the front face toward the rear face is determined by the size of the largest electrical component in the case of an electrical equipment box having two spaces (one on the left and one on the right). Consequently, it is likely that some of the space inside the electrical equipment box will be wasted. Moreover, if one attempts to reduce the size of the outdoor unit when viewed from the top face, the amount by which the electrical equipment box protrudes toward the rear face will be larger, the flow of air from bottom to top inside the casing will be impeded, and the air flow resistance will increase. Consequently, there is the possibility that the blowing performance of the blower fan will decline and that noise will increase.
Thus, it is difficult to reduce the size of an electrical equipment box that is constructed to have two spaces, one on the left and one on the right, in which the electrical components are arranged in a planar manner arranged generally along a horizontal plane. Although it is feasible to divide the electrical equipment box into a plurality of electrical equipment boxes arranged in places that do not impede the blowing work of the blower fan, such a configuration would increase the number of assembly steps required for the electrical equipment box and make it less convenient to access the electrical equipment box after the outdoor unit has been installed. It would also be difficult to arrange the electrical components such that they are separated according to function and characteristics.